Process of converting crude iron into malleable iron or steel



(No Model.) l G.. L' PROCESS 0E GONVEETING GRUDE IRON INTO MALLEABLE IRO-N 0E STEEL. No. 400,010. Patented Mar. 19, 1889.

y if Lf- 6 m W Nrrnn Tatras GUSTAVE L. ROBERT, OF STENAY, FRANCE, ASSIGNOR TO JOI'IN lVESLEY BOOKNV ALTER, OF SPRINGFIELD, OHIO.

PROCESS OF CONVERIING CRUDE IRON INTO MALLEABLE IRON OR STEEL.

SPECIFICATION forming part of Letters Patent No. 400,010, dated March 19, 1889.

Application filed November 19, 1888. Serial No. 291,189. (No model.)

To all whom t may concern.'

Be tknown thatI, GUsTAvn Louis ROBERT, a citizen of the Republic of France, residing at Stenay, Department of the Meuse, Republic of France, have invented a new and useful Improvement in the Process of Converting Crude Iron into Malleable Iron or Steel, oi' which the following is a full, clear, and exact specification. v

In the use of the rapid method of converting crude iron into malleable iron or steel a converting-blast of aeriforln oxidizing agent, as air, has been projected upon a portion of a body of molten metal in such manner as to contact at one time With a limited part only of said body to impart a violent agitation to such part only, and also to impart to the main body of the metal a flow or gyration which repeatedl y brings every portion Within the area 2o of violent agitation without creating currents or movements that Would tend to carry into the body ot' the metal any eliminated particles that are upon the surface thereof. The violent agitation results in separating the metal and theimpurities, andthe latter, once freed from their adhesion to the metal, remain upon the surface of the bath, owing to their lighter specific gravity, while the contact of the converting agent with the exten ded surfaces of metal resulting from stripping off and breaking up successively small bodies of metal by the action of the-blast causes a rapid oridizing action and the formation of impurities which are separated from the metal carried with the blast and deposited and retained collected together upon the surface of the bath. In this mode of conversion there are certain variable conditions inherent in the nature of the process, which, if not fully met and provided for, affect in. varying degrees the ultimate result produced. First, the metalY such blast is strong and powerful, so as to overcome the inertia of the mass, and that even in such case the initial movements are necessarily slow. There is a greater tendency to overoxidation when the mass is in a stationary or comparatively stationary state than when it is gyrating, so that as a result of the slow gyration of the mass at the beginning of the operation there is relatively' less metal presented to the oxidizing agent, and 6o the combustible elements of the bath are not exposed with such rapidity as to take up all of the oxidizing agent, and as some considerable time necessarily elapses before the inertia of the mass is fully overcome and the requisite gyratory motions secured there is a tendency of the surplus oxygen to attack and act With destructive effect upon the metal. Thus While the oxygen may quickly burn out the carbon and silicon and other combustible 7o elements held by t-he iron, the surplus of oxygen in the blast, owing to the limited amount of metal presented to its action, seizes upon the iron itself in the absence of other conlbustible elements to take it up and rapidly forms therewith an oxide of iron, resulting not only in a great Waste of metal, but in the production of impurities Which deteriorate the quality of the product. As the process continues and the metal is presented more 8o `rapidly to thev blast, presenting increased quantities of the elements to (the oxygen, there is an increased combustion and heat, which results in rendering the metal more iiuid and therefore more mobile, so that the blast will impart a more rapid gyration thereto, and this may increase unt-il the movement is too rapid, tending to cause the impurities generated in the process of conversion to be returned to and remixed with the body of the metal in the bath. As the combustible elements contained in the iron are gradually reduced in amount as the process is continued, and the proportion of combustible matter subjected to the action of the blast and capable 9'5 of combining with the oxygen becomes gradually less and less, the amount of oxygen in the blast presented to the metal becomes relatively greater toward the termination of the process, and this results in a further excess roo of oxidizing` agent, which, in the absence of any material with which to combine, seizes upon the iron, forming an oxide with the detrimental el't'ects before referred to.

It is the object ot this invention to overeome the detects in the rapid mode ol.' conversion, as above set forth, and to provide means 'l'or maintaining more constantand fixed relations throughout the whole period of the act of conversion, and this object is eil'ectcd by varying the position and volume of the blast, so that its mechanical and convert-in g action will each vary with the varying conditions of the metal.

For the purpose ot illustratingl the invention and one means ot' carrying it into eiteet, l have shown in the accompanying drawings sectional elevations ot' an ordinary converter, three lfigs. l, il, and .il illustrating the operations and conditions at three diit'erent stages in the process.

The mass ot' metal constituting the bath X is passed in a molten torni into the converter A, as usual. The latter is tilted so as to carry the surface oli' the metal to the tuyeres a, as shown in Ifig. l, that the e(inverting-blast may be thrown upon the surface of the metal.

In order to vary the volume and pressure ot' the blast tor the purpose described, I throttle the passage through which the air is conducted to the tuyeres in any su itable mann er as, t'or instance, by an ordinary valve controlled in its position by a handleJi-a'nd While different means may be einployed l or varying the height oi' the blast in respect to the normal surface of the metal, I prefer to ef'li'ect this result by tilting the converter to different positions during diifterent stages ot' the operations. Thus, at the beginning ot the operas tion the converter is tilted so that the blast, which is then at its maximum pressure, is applied upon the surface in sueh manner as Will overcome as speedily as possible the inertia ot' the metal and quickly impart to it the desired speed of gyratimi.

In applying the blast in the beginningl otthe operation it is projected at such an angle as to collie into contaetu'ith a more extended surface of the metal than at subsequent stages of the operation t'or the purpose ot' avoiding the over-oxidation that would result from applying the blast violently and in large volume upon a limited area of the metal. After the metal has acquired the desired speed of gyratory motion, the converter is tilted to lower the bath to its position, (shown in Fig. 2,) so as to act upon a more limited area oll the metal at one time, but with a greater atomizin g or dividing effect, bringing the particles ot' iron into more intimate contact with the air and increasing t-he combustion and heat and the Vfluidity ot the metal, and with. this change Vin the position of the blast I begin to reduce the volume and the pressure, proportioning such. reduction to the effect desired to be produced, as may be determined by indi cations easily recognized by any one skilled in the operation ot' conversion. As the process eontinnes, the converter is :Further tilted toward the position shown in Fig. 3, and from this on the pressure and position of the blast are so varied or maintained as may be necessary to secure the desired result.

By the oljieration above described I can readily avoid the tendency to overoxidation that results at thebeginning oi' the rapid pro cess of ollversion Ytrom the inertia of the metal, the sluggisl'messol its movements, and t'romV the dit'liculty ot imparting to it the dcsired speed ot gyra-tion by a blast applied locally at the surface, without alsosupplyin g an excess of the oxidizing agent.

I claiml. The Within-deseribed improvement in the conversion of crude iron into malleable iron or steel, consisting in apliilying a blast of air to the surface portion ot' a body ot' molten metal at a maximum pressure at the beginning of the operation t'orthe purpose of overcoming the inertia oit the metal and `imparting thereto the proper speed of gyratory motion, lowering the levelA of the blast as the process continues without carrying it into the body of the metal, and varying the pressure and volume ot' the blast to meet the requirements of the reduction in the conilnistible elements ot' the iron and theinereased fluidity ot' the metal, substantially as set forth.

In the process ot converting crude iron into malleable iron or steel by the action ot' `a blast applied locally upon the surtaee ot the mass olil molten metal, varying the level of the blast and the volume and pressure thereof in proportion as the metal increases in speed ot gyration and liuidity and as the combustible elements are eliminated, substantially as set forth.

In testimony whereof I have sign ed my name to this specification in the presen ce ot two sul scribing witnesses.

('l'U'S'lAVE L. 'OllElt'l Witnesses:

Guo. ll. GRAHAM, l`. L. lfnlmnnn.

TOO 

